The science club advisor asked club members what science courses they
liked. Eighteen members said they liked physics, 17 liked chemistry,
and 10 liked biology. However, of these, 9 liked physics and
chemistry, 4 liked biology and chemistry, 2 liked physics and biology,
and 2 liked all three. How many science club members were interviewed?

Two questions: 1) There are 1000 lockers numbered 1-1000. Suppose you
open all of the lockers, then close every other locker. Then, for every
third locker... 2) A certain substance doubles in volume every minute. At
9:00 a.m. a small amount is placed in a container...